devstack ubuntu broken pipe error (current and rocky)

Seems I'm trying to do something a little less common which is install devstack on Ubuntu 18.04.02 LTS without doing a conjure-up or something similar. The machine is fully updated/upgraded. No new packages added. Git was already a part of the server install.

My goal is to do something like tripleo (OpenStack on OpenStack) on Ubuntu.

So the idea was install devstack on a single machine.

So did the git clone against master
put a local.conf in, (even tried the exact example on this page (https://docs.openstack.org/devstack/latest/guides/single-machine.html)) (https://docs.openstack.org/devstack/l...)
ran "./stack.sh"

If I use master the error occurs on line 540. If I got to stable/rocky it appears on 533.

So perhaps the issue I'm reporting is that the docs for single machine maybe imply a simpler config file than what is necessary:

Run DevStack¶
Now to configure stack.sh. DevStack includes a sample in devstack/samples/local.conf. Create local.conf as shown below to do the following:
Set FLOATING_RANGE to a range not used on the local network, i.e. 192.168.1.224/27. This configures IP addresses ending in 225-254 to be used as floating IPs.
Set FIXED_RANGE and FIXED_NETWORK_SIZE to configure the internal address space used by the instances.
Set FLAT_INTERFACE to the Ethernet interface that connects the host to your local network. This is the interface that should be configured with the static IP address mentioned above.
Set the administrative password. This password is used for the admin and demo accounts set up as OpenStack users.
Set the MySQL administrative password. The default here is a random hex string which is inconvenient if you need to look at the database directly for anything.
Set the RabbitMQ password.
Set the service password. This is used by the OpenStack services (Nova, Glance, etc) to authenticate with Keystone.
local.conf should look something like this:
[[local|localrc]]
FLOATING_RANGE=192.168.1.224/27
FIXED_RANGE=10.11.12.0/24
FIXED_NETWORK_SIZE=256
FLAT_INTERFACE=eth0
ADMIN_PASSWORD=supersecret
DATABASE_PASSWORD=iheartdatabases
RABBIT_PASSWORD=flopsymopsy
SERVICE_PASSWORD=iheartksl

I'm posting this so that anyone who has the same problem and can't find an answer is hopefully helped over the hump.